All right, some quick comparisons with codeBeamer Managed Repository (MR).
* MR against Gitosis
In terms of access control, MR has the concept of "role", and it makes our security model more fine grained. Permissions
can be set by role. One user account can have multiple roles. Roles are project-dependent. When you add a group to a
project, you can assign multiple roles to the group (which is equivalent with assigning those roles to each group member
one by one).
On the other hand, MR has a much broader scope than Gitosis. MR helps you to manage your repos, to track your
tasks/bugs/issues, to follow commit activities, to browse repos in the web, can be extended using its APIs, etc. (And
you don't have to install and maintain Git extensions for this.)
* MR against Gitolite
Pretty much the same applies here as well.
* MR against GitHub & Gitorious
Probably the most significant difference is that MR is available as free download, and can run behind your firewall.
MR was derived from the source code of our commercial product codeBeamer. CodeBeamer is a full-blown enterprise
collaboration solution, thus MR is likely to focus more on the enterprise needs, not on the "social" aspect.